The present invention relates to an electronic circuit package assembly with an electronic part mounted thereon, and a method of producing the same.
One of conventional TAB (Tape Automated Bonding) technologies for electronic circuit package assemblies is disclosed in a reference entitled xe2x80x9cBasic Course for Electronics Mounting Technologiesxe2x80x9d, edited by Society for Hybrid Microelectronics (Japan) and published by Industrial Research (Japan), Vol. 1.
Among various bare chip mounting systems, a TAB system is ranked with a wire bonding system and a flip chip bonding system. Basically, the TAB system consists of ILB (Inner Lead Bonding) and OLB (Outer Lead Bonding). ILB connects the electrodes of an LSI (Large Scale Integrated circuit) chip and a carrier tape via bumps. OLB connects the LSI chip having leads stamped out from the carrier tape to a substrate. Such a basic process is taught on page 261 of the above-mentioned reference. Specifically, by the OLB, the LSI chip with the leads, i.e., a TCP (Tape Carrier Package) is stamped out (with or without the tape) and then connected to a circuit board, as taught on 265 of the same reference.
In the above configuration using the TAB system, a tape carrier section is connected to a substrate by lead bonding. A problem with this configuration is that an organic film is flexible and cannot uniformly maintain the gap between the tape carrier section and the substrate, deteriorating the solder connection. Another problem is that the solder implementing the connection alone is apt to come off or break and lacks in reliability as to migration. This is because the package is low in heat resistance and humidity resistance and susceptible to mechanical stresses.
It is therefore an object of the present invention to provide an electronic circuit package assembly insuring reliable connection using solder, and a method of producing the same.
It is another object of the present invention to provide an electronic circuit package assembly capable of reducing mechanical stresses, and a method of producing the same.
It is still another object of the present invention to provide an electronic circuit package assembly having improved reliability as to heat resistance and migration, and a method of producing the same.
It is a further object of the present invention to provide an electronic circuit package assembly allowing a gap between its organic insulating film and a substrate which is stably controlled, and a method of producing the same.
In accordance with the present invention, an electronic circuit package assembly includes an electronic component. A first substrate has a surface on which the electronic component is mounted, and first electrodes electrically connected to the electronic component. A second substrate has second electrodes thereon. A sheet is interposed between the first and second substrates and has connecting portions electrically connecting the first and second electrodes.
Also, in accordance with the present invention, a method of producing an electronic circuit package assembly has the steps of laying a sheet formed of thermosetting resin sheet having solder buried therein on a substrate on which wiring electrodes are formed, mounting to the sheet an organic insulating film carrying an electronic part thereon provided with outer leads, and executing heat treatment for causing the solder to melt and connect the wiring electrodes and outer leads, and for causing the sheet to set.